Indicating system



Feb 6, 1934. A T 1,945,666

INDI'CATING SYSTEM Filed Nov. 22 1928 Fig 2.

Inventor: Cl de EStewave, (id ray His Attorneg.

A 1,945,666 PATENT OFFICE INDICAI'ING SYSTEM ClydeLStewsrLDremelGenerallleetrie E irates-Ism Oompany,aoorporationol New York November2:, 1m No. sense 9 Claims. m-sss) My present application relates tocertain improvements in the system disclosed in my former application,Serial No. 260,168, filed March 8, 1928, entitled Supervisory controlsystems corresponding to British Patent 307,469. it deals withindicating system which, while notilimited thereto, is particularlyadapted foruse in connection with supervisory systems of the typetherein disclosed. 1

In supervisory control systems in which synchronously operated rotaryselector switches are employed, one in the dispatchers station and the.

a other in the remote station, by means of which line conductorsextending between the two stations are connected to any one of apluralityof supervised devices in the remote station and to acorresponding control key or indicating device lamps one of whichcorresponds to each posi-' tion of the selector switch in thedispatcher's station and which is lighted whenever the switch comes torest in any oir-normalposition.

. 6 while this means produces a very reliable indication and one that issuitable for most practical purposes, it sometimes occurs whereimportant circuit breakers are controlled and supervised by theequipment that additional means are desired to indicate the position ofthe re-.

mote switch, thereby to eliminate any possibility of a discrepancy inthe position of. the two switches resulting in error in the controloperatlO 1.

zccordingly one of the objects of my invention is to provide means forindicating to the operator the position of the selector switch in theremote station independently of the position of the switch in thedispatcher's station.

'-In large supervisory systems where a great many remote devices arecontrolled and supervised through the same line conductors it isdesirable, for reasons of economy, that'the same equipment be utilized,in so far as possible, to indicate a large number of positions of theremote switch, or switches where more than one.-are employed.Accordingly another purpose of my ir'i'vention is to provide equipmentwhich is associated with the switch in the remote station whereby asimple indicating device such as a frequency meter having. for example,ten frequency responsive vibrating reeds. may be utilized in thedispatchers station to indicatev a much larger number of positions ofthe remote to or tend between the stations. The conductor s ineration ofthe switches a and A,

A further purpose of the invention is to provide a system for indicatingquantities, which while having particular utility in connection with theindication of the positions of a remote element such as the remotedistributor switch of the supervisory system above indicated. is notlimited thereto but may be employed in a wide variety of applications.

The novel features which I believe to be characteristic of my inventionare set forth with particularity in the appended claims. My inventionitself, however, both as to its organization and method of operation,together wifl further objects and advantages thereof may best beunderstood by reference to the following description taken in connectionwith the accomilmyins drawing in which Fig. 1 represents an embodimentof my invention, and Fig. 2 represents a detail.

Referring to Fig. 1 of the drawing I have shown at the lower portionthereof, in as great detail as is necessary for an understanding of myinvention, a supervisory control system with which my present inventionhas particular utility. This system includes a selector switch A at thedispatcher's station and a selector switch A at a remote station, eachof which comprises a plurality of banks of contacts and associatedwipers s n i and c. These selector switches are joined by four lineconductors s i c' and a which excludes a pair of polarized relays p andp, one of which is located in each of the stations, and which areemployed for synchronizing the op-' Conductor c which joins wipers ofthe banks c of selector switches Aand A is used for transmittingimpulses to eifect control operations at the remote stations. Conductori which joins the wipers ofthebanksiofswitchesAandA'isusedfortransmitting impulses to control the indicating equipment at thedispatchers station. Conductor p is a common return or ground wire forall of the circuits extending between the two stations. e

An understanding of the supervisory system may best be had by referenceto its operation. Let us assume that the operator at the, dispatcher'sstation desires to operate switch 14 at the remote station to itsclosedpositiom- He'--wili o first open the contacts of selecting key 14'corresponding to the remote swltch which is to be operated. He will thenclose the contacts of starting key I: and thereby start the selectorswitches into synchronous operation. This operation results fromcompleting a circuit which extends from the positive side of the battery16 in. the dispatcher's station through the keyv k, normal contact andwiper of thebank i of switch A, conductor 1', wiper and normal contactof the. I.

bank i of switch A, winding of relay 16 and ground conductor g'to anintermediate point upon the source of potential 15. Relay 16 will thenoperate to close its contacts, thereby completing a circuit extendingfrom the positive side of the battery 15' in the remote station throughthe contacts of relay 16, normal contact and wiper of the bank s ofswitch A', windings of polarized relays p and p, wiper and normalcontact oi the banks'of switch A the selecting key,

which is associated with-the normal contact of bank s of switch A andwhich is closed except under certain conditions when it is desired tostop the selector in its initial position, to the negative side of thebattery 15. Polarized relays p' and p, which constitute thesynchronizing relays of the system, will then actuate their armaturesto-the upper position. In this position relay 1: will complete a circuitextending from positive potential at the upper contact of relay 9throughthe contacts and winding of motor magnet 17 of switch A and wiperand normal contact of the bank 11 of switch A to negative potential.Similarly relay p at the remote station completes a circuit whichextends from neg ative potential through the-contacts -of relays 9'contacts and winding of motor magnet 17' of switch A and wiper andnormal contact of the bank 12. of switch A to positive potential.

Motor magnets 1'7 and 17' are connected to the wipers of theirrespective switches through a suitable ratchet and pawl mechanism suchthat at each deenergization thereof, the switch is actuated one stepforward'in the direction in which it is adapted to rotate; Uponenergization, as previously described, motor magnets 17 and 17'deenergize themselves, thereby stepping the selector switches to theirfirst off-normal position. Since alternate contacts of the banks 8 and n'of each of the switches are connected to points of opposite polarity onthe respective batteries 15 and 15, it will be seen that in the nextposition of the switches A and A, the current in the circuit previouslytraced including the polarized relays p and 9' will be reversed, and thearmatures of these relays therefore will be actuated back to theposition shown in the drawing. When this occurs the motor magnets 17 and17' are again energized and in operating advance the wipers anotherstep. This operation would continue were it not that the operator, priorto closing the starting contact 7:, separated the contacts of the ingkeys. In so doing the second ofl-normal conin the drawing to the othertact of the bank a of switch A was disconnected from the battery, andhence when the selector switches engage'this contact the polarizedrelays p and p are deenergized and the switches stop in this position. a

The operator will now operate key14" in the dispatchers station,corresponding to the switch 14 in the remote station, from the positionshown position and, in so doing, will reverse the current in a circuitwhich extends fromthe positive side of battery 15 through the uppercontacts of key 14' second contact and wiper of the bank 0 6f switch A,conductor e and second ofl-normal contact of the bankcofswitchA',windingof polarlzedrelay18 atthe remote station and ground conductor aback to an intermediate point upon the source of potential 15. Relay 18will the'noperate its armature to the lower position, thereby energizingthe closing coil of the'switch 14 causing that switch to operate toitsclosed position. In its key 14' of the select-.

prise tuning forks connected and closed position the switch 14 willcomplete a circuit which extends from the negative side of the source ofpotential 15' at the remote station, through the interlock 11 of theswitch 14 and its upper stationary contacts, second off -normal contactand wiper of the bank 2' of switch A, conductor i,- wiper and secondoiI-normal contact of the bank 1' of switch A, winding of relay 12 andconductor a back to an intermediate point on the source of potential 15.Polarized relay 12 will then operate its armature from the positionshown to the opposite position, thereby deenergizing a red lamp 1' andenergizing a green lamp 9 indicating that the switch 14 is in the closedposition. If the operator desires again to open the switch 14, he willreverse the position of the key 14", thereby reversing the polarity ofthe current in the polarized relay 18, which in turn energizes the tripcoil of the switch 14. As the switch 14 returns to the position shown inthe drawing, the interlock 11 engages its lower contacts, therebyreversing the polarity of current in the polarized relay 12 which inturn extinguishes the green lamp 0 and relights the red lamp r.

In returning the selector switches to their normal positions, theoperator will again close the contacts 14', thereby again energizingpolarized relays p and p causing synchronous operation of the selectorswitches to be resumed and continued until the wipers return to theirnormal positions. When this occurs the circuit of the po-' larlzedrelays is interrupted at the contacts of relay 16 and the switches stopin this position.

After having closed the starting contacts K, it is necessary for theoperator to have an indica- 110 tion of the position in which theselector switches A and A come to rest since, due to faulty operation ofthe equipment, they may not always stop in the position determined bythe selecting key the contacts of which were opened by the oper- 115ator. An indication of the position of the switch A in the dispatchersstation may be had by means of indicating lamps (not shown), one ofwhich is lighted whenever the switch A is in any position. This meansforms a very reliable indiea- 120 tion also of the position of theswitch A, and one which is suitable for most practical purposes of theequipment. However, in the supervision of important circuit breakerswhere an erroneous operation is likely to result in great damage to mentshown in the upper portion of the drawing together with a simplevibrating reed frequency meter 13 in the dispatchers station. This meanscomprises a transmitter'including a plurality of oscillation generators1 to 10', which may comarranged in any well known manner such as in themanner shown in Pig. 2. These oscillation generators are all adapted toproduce alternating current of dlfl'erent frequency in their outputwindings 38. These windings are connected in parallel and arranged tosupply current through condensers 21 to the line conductors; c and 1''.At the dispatcher's station the frequency meter 13 is connected throughcondensers 22 to these line conductors whereby it responds to thefrequency of 150 ever the switch A' occupies the corresponding position.To selectively complete the circuits of these relays a wiper is providedupon the shaft of the switch A' which operates over a bank of contactsit, each of which contacts are included in circuit with one of therelays S. Each of the selecting relays have one ormore contacts each ofwhich is included in the energizing circuit of one of the tuning forkgenerators, these circuits being periodically completed by means of arotary switch 19 presently to be described.

In the form shown the rotary switch 19 comprises a selector switch ofthe same type as switches A and A having three wipers B, C, and

a D. The wiper D is utilized to control the. energizing circuits of thetuning forks which circuits, in sheet, constitute the frequencydetermining circuits of the transmitter. Wipers B and C together withrelays, which are later to be indicated and which cooperate with wipersB and C constitute a motor mechanism for operating the rotary switch.

For a better understanding of the operation of the transmitter, providedin accordance with my invention, let us assume that the switches A and Ahave been operated to the second olfnormal position, as previouslydescribed. When either of the switches A or A leaves its normal positiona circuit is interrupted which extends from the negative side of thesource of potential 15 through normal contact and wiper of the bank 0 ofswitch A, conductor 0', wiper and normal contact of the bank 0 of theswitch A, relay 20, the positive side of battery 15', intermediate pointof battery 15' and conductor a to the intermediate point of the sourceof potential 15. Relay 20 is then deenergized and its armature isoperated to the circuit-closing position. Upon deenergization of therelay 20 the driving circuits for operating the rotary switch 19 are setinto operation, and the wiper D then periodically completes each of theenergizing circuits of thetuning forks which have been selected by the Srelays, in succession such that the vibrating reeds of the frequencymeter at the dispatcher's station vibrate in resonance with-thefrequency, or frequencies, of the transmitted currents therebyindicating the position of the remote switch.

Upon deenergization of the relay 20 a circuit is completed which extendsfrom the positive side of the source of potential 23 through thecontacts of relay 20, wiper C in its normal position, relay 24 andarmature and lower contact of relay 25 to the negative side of thesource of potential 23. Reley24 then energizes thereby connecting motormagnet 26in shunt with its own winding. Motor magnet 26 operates itsarmature thereby deenergizing itself and stepping the wipers B, C and Din a clockwise direction on to their first contacts. The first contactof the banks with which wipers B and C cooperate are both connected topoints having the same polarity as the normal contacts of these banksand, according y, the motor magnet 26 is again energized, stepping thewipers B, C and D on the second contact. In this position relay 24 isshort circuitedthro shwiperc anditssecondeontact which contact isconnected to the same side of the battery as the opposite terminal ofthe coil of relay 24. After a time interval, its armatures are actuatedto the right thereby completing a circuit which extends from anintermediate point on the battery 23through the right-hand armature andcontact of relay 24, winding of polarized relay 25, wiper B and secondcontact of the associated bank back to the negative side of the sourceof potential 23. Polarized relay 25 will then actuate its armature tothe upper position thereby disconnecting one side of the winding ofrelay 24 from the negative side of battery 23 and connecting it to thepositive side of I battery 23. Relay 24 is now again energized therebycausing a subsequent actuation of the motor magnet 26 and a steppin ofthe wipers B, C and D onto their third contacts. when the wiper C stepsfrom its second to its third contact, it disconnects one terminal ofrelay 24 from the negative side 'of battery 23 and connects it to thepositive side of battery 23, which in turn again short circuits anddeenergizes this relay. Its armatures are then actuated to the right,after a time interval, again completing a circuit for relay 25. Sincewiper B is now on its third contact, however, the polarity of thecurrent in relay 25 will be reversed, and this relay will operate itsarmature back to the position shown in the drawing; Since the alternatecontacts of the banks associated with wipers B and C are connected topoints of opposite polarity, it will be seen that this operation willcontinue as long as the contacts of relay 20 are closed or as long aseither oi the switches remains in. an oil-normal position, the wipers B,C and D rotating continuously over their respective banks of contacts.

. Since the selector switch A is in its second onnormal position, acircuit is completed for the winding of relay S: which extends from thenegative side of the battery 23 through the wiper and second off-normalcontact of thebank t, actuatintermediate point on the source ofpotential 23. Relay S: controls an energizing circuit for oscil- 1 ingwinding of relay S2 and conductor 27 to an lation generator '2', thiscircuit extending from the negative side of battery 23 through conductor28, oscillation generator 2, contacts of relay 8:, contacts 29 and 30 ofthe bank associated with wiper D of the switch 19 and conductor 27 to anintermediate point on the source of potential 23. Thus whenever thewiper D engages either of the contacts 29 or 30, the energizing circuitof genbration of the vibrating reed 2 in the proper pe-' riod, he willbe informed that the remote switch is on its second off-normal contact.

Let us assume that the switch A has been operated to its 12th contact.The operation will of course be as previously described, with theexception that relay S11 is energized through the twelfth off-normalcontact of bank t. This relay controls two energizing circuits, one forgenerajtor 1' and the other for generator 2. The cirjcuit for generator1' includes the left-hand armature of relay S1: and the contacts 29 and30 of the with wiper D of the switch 19. The energizing circuitfor'generator 2' includes the right-hand armature of relay Sn andcontacts 31 and 32 of'the bank with wiper D. Thus the wiper D firstpasses over contacts 29, thereby causing operation of the generator 1',and then over contacts 31 thereby causing operation of generator 2'after which an interruption occurs in which no generator is encontact.

If we now assume that the selector switch A is upon its 21st contact,relay S21 will be energized thereby again establishing energizingcircuits for generators 1' and 2,- but in this case the energizingcircuit of generator 2' is connected to the contacts29 and 30 throughthe left-hand armature of the relay S21,and the energizing circuit ofgenerator 1' is connected to the contacts 31 and 32 through theright-hand armature of the relay S21. Thus in this case as the switch Drotates first vibrating reed 2 will be actuated and then vibrating reed1 in quick succession after which an interruption will occur. Therepetition of this vibration of these reeds, first 2 and then 1, willinform the operator that switch A is on'its 21st contact.

If we assume that the switch A is in engagement with its twenty-secondcontact, relay Sn will be energized. This relay connects the energizingcircuit of generator 2' to contacts 29 and 30 through its left-handarmature and to contacts 31 and 32 through its right-hand armature.

Thus during operation of rotary switch D vibrating reed 2 will vibratetwi'cein rapid succession after which a long interruption will occur,and then the indication will be repeated thereby informing the operatorthat the switch is on its twenty-second contact. -It will be apparentthat this indication is distinct from that produced in response toactuation of switch A to its second oil-normal position, since in thatcase reed-2 vibrated in about equal intervals of time rather than'asabove described. a It will be noted that each .of the-relays S are ofthe slow-closing type. The time interval provided in connection withthese relays is such that they do not respond as the wiper of the bank tpasses rapidly over its contacts as in moving from a normal position toone of the other positions but only respond when this wiper definitelycomes to rest upon a selected contact.

It will now be apparent that eacli group of alternating current impulseswhich is produced by the transmitter includes as many impulses as thereare digits in the number of the position which is occupied by theswitch, and that the frequency of each impulse corresponds to theinteger of the digit which the particular impulse represents in thenumber to be indicated by the group of impulses. Where a plurality ofselector switches are employed in the remote station as, for example, inthe manner shown in my above mentioned copending application, the numberof the position to be indicated may well have more than two digits. Suchpositions may, of course, be indicated by utilizing as many armatures oneach of the series of selecting relays S, which correspond to thesepositions as there are digits in. the number to be indicated and may beomitted. In any case the interval be-.

tween groups is greater than that between the.

different impulses of any group. In this way the impulses are clearlydivided into distinct roups which may be, readily read as positionnumbers on the frequency meter 13.

It will of course be apparent that the speed at which the rotary switchD revolves may be controlled by varying the time delay of the relay 724. The duration of each of the alternating current impulses as well asthe duration of the time intervals between successive impulses may alsobe controlled by adjusting the number 01 contacts in each set and bysuitably spacing the contacts, or sets of contacts 29 and 30, and 31 and.32 in the bank of contacts.

In Fig. 2 I have shown the circuit connections of a tuning forkoscillation generator which may be utilized in connection with myinvention. This'circuit'is a well-known arrangement having an energizingcoil 33 which is connected in shunt with the battery terminals 34;. Whenthis coil is energized a variation is produced in the currentfiowingthrough the circuit extending from one side of the battery at one of theterminals 34 through the microphone'button 35, Primary winding oftransformer 36 back to the other side of the battery. This variation incur-.

rent in the transformer 36 sets up a current in the loop circuit 37which in turn affects the tuning fork causing a continuation of thevibration thereof and, hence, the production of alternating currentwhich appears in theoutput circuit as. 4

It will of course be understood that while I have particularly mentionedthe use of tuning forks in the transmitter, as described, I do not wishto be limited thereto since other means for producing oscillations ofvariable frequency may be used as well. Such modifications are of courseto be regarded as within the scope of my present invention.

While I have shown a single embodiment of my invention, it will ofcourse be understood that I do not wish to be limited thereto since manymodifications, both in the circuit arrangement and in theinstrumentalities employed, may be made without departing from thespirit and scope of my invention, 'as set forth'in the appended claims.

What I claim as new and desire to secure by Letters Patent of the UnitedStates, is:

1. In combination, a movable element, means for operating said elementto a plurality of positions, a plurality of oscillation generators, saidgenerators being arranged to produce oscillations of differentfrequencies, frequency responsive indicating means, a rotary switchhaving a wiper and a plurality of stationary contacts, means forrotating said wiper over said contacts, and means'responsive to theposition of said element for selectively establishing connections tosaid generators through said wiper and certain of said contacts so thatthe rotation of said wiper causes said generators to supply to saidindicating means oscillations of different frequencies in apredetermined sequence determined in accordance with the positions ofsaid element.

2. In combination, a movable element having I a plurality of positions,remotely controlled the rotation ofsaid wiper renders a predeterminedcombination of said generators operative in a predetermined sequence,and indicating means ata remote point controlled by the frequency of theoscillations generated to indicate the position of said element.

BxThe combination, in a remote control system,- a dispatcher's station,a remote station, a movable element in the remote station having anormal position, means controlled from the dispatchers station foroperating said element from said normal position to any one of aplurality of other positions, alternating current transmitting means inthe remote station, means responsive to operation of saidelement fromits normal position for actuating said transmitting means, meansresponsive to the position of saidelement for controlling the frequencyof the currents transmitted and means in the dispatchers stationcontrolled by the frequency of the currents transmitted for indicatingtheposition of said element." 7 A I A 4.'The combination. in a remotecontrol system, a dispatcher's station, a remote station, conductorsJoining said stations, as rotary distributor switch in said remotestation connected to said conductors. means for, actuating said switchto predeterminedpositiims, means for transmitting alternating current ofpredetermined frequency over said conductors to the dispatcher's stationincluding a'plurality of sources of alternating I current havingdifferent frequencies, a rotary switch having a wiperand a plurality ofstationary contacts, means for. rotating said wiper over said contacts,and means responsive to the position of said distributor switch forselectively establishing connections through said contactsandwipertocertainofsaidsourcessothatthe rotation of' said wiper causes acode of current impulses of diflerent frequencies to be transmitted oversaid conductors'and means in the dispatchers station responsive to thefrequency of said alternating current impulses for indicating theposition of the remote switch.

- ii. The combination. with an element which is operable from a normalposition to any of a plurality of other positions, means for indicatingat a remote point the position of said element, comprising meansresponsive to movement of said element from its normal position'fortransmitting to' the remote point mccessive groupsofalternating currentimpulses, the current transmitted during the different impulses of eachgroup being of different frequency, the frequency of each impulse being,determined by the positionof said element and moment the remote pointresponsive to the frequency of said alternating currentfor indicatingthe position of said element. 7

6. The combination. with an element which is operable froma normalposition to any of a plurality of other positions, means for indicatingat a remote point the position of said element comprising meansresponsive to movement of said element from its normal position fortransmitting to the remote point a group of alternating currentimpulses, the current transmitted during each of the diilerent impulsesbeing of diflerent frequency, each of said frequencies being determinedby the position of said element and means at the remote point responsiveto the frequency of said alternating current for indicating the positionof said element.

"l. The combination, with an element which is operable from a normalposition to any of a plurality of other positions, means responsive tomovement of said element from its normal position for transmitting tothe remote point alternating current having a predetermined combinationof frequencies, each of the frequencies comprising said combinationbeing determined by the position of said element and means at the remotepointresponsive to said frequencies for 7 indicating the position ofsaid element.

8. The combination, in a remote control system, an element having anormal position, means for actuating said element to a plurality ofother positions, a rotary switch having a wiper and a plurality ofcontacts, driving means for actuating said wiper over said contacts,alternating current transmitting. means including a plurality offrequency determining connectio each of saidconnections including one ofsaid contacts. means responsive to movement'of said element from saidnormal position for actuating said driving means, means responsive totheposition of said element selectively to'establish certain of saidconnections including said contacts therebytocausesaidtransmittingmeanstotransmit current having predeterminedfrequency upon each engagementof said rotary switch with contactsincluded in said certain connections and indicating means responsive tothe frequency of said current. r

9. In combination, a'flrst, station, asecond station, a-distributorswitch in said second station, means for actuating said distributorswitch to predetermined positions, and means for indicating at saidfirst station the position of the distributor switch when itremains inany of said predetermined positions a predetermined time includingconductors joining said stations, means at said second station fortransmitting over ,said conductors a combination of impulses ofdifferent frequencies including a plurality-of sources of alternatingcurrent having different frequencies, a rotary switch having a wiper anda plurality of stationary contacts, means for effecting the rotation. ofsaid wiper over said contacts when said distributor switch remains inany of said predetermined positions for a predetermined 135 tiondistributor switch to be transmitted over a said conductors. andfrequency responsive indicating means at said first station responsiveto said impulses. x

' "CLYDE ESTEWART.

